1. Field of the Invention
This invention relates to a liposuction apparatus and method. More particularly, this invention relates to a liposuction apparatus optionally having a sonic or ultrasonic source with an axial lumen passage, and is ideally suited for smooth continuous fat removal.
2. Description of the Prior Art
Liposuction, which literally means "fat suction", is a technique that pulls fat out of the body by means of teasing, pulling, scraping or suction. It can be used to reduce the volume of fat in many regions of the body, but is particularly effective in areas such as thighs and abdomen, which contain genetically determined fat not responsive to diet or exercise. Liposuction is currently an established modality in cosmetic surgery, performed by surgeons as an elective operation, and is one of the most common procedures in medicine.
All existing ultrasonic liposuction devices used in surgery, especially those with short rigid shafts, can cause complications and trauma by failing to have proper temperature control and improper placement in addition to increased entrance wounding.
A commonly accepted liposuction technique utilizes a cannula with a blunt closed bullet-shaped tip rather than an open tip or a pointed or sharpened tip. This cannula is a metal tube, about the size of a pencil, which is attached to a suction pump. The cannula, with its rounded tip, is sometimes passed through the fat first, without suction, to develop the proper passageway. Then suction is applied and the surgeon continues passing the cannula through the fat tunnels with repeated radial thrusts on several levels of the tissue. Adipose tissue is aspirated through a hole in the side of the cannula near its distal end. The cannula must be moved back and forth through each tunnel. Problems associated with this technique are similar to those experienced with the older methods of liposuction and include: oversuctioning, need for many entrance incisions, difficulty positioning patient, bleeding and resistance to passage in fibrous tissues.
Today there exists a wide variety of cannulas which allow surgeons to work more skillfully. For example, there is a bullet shaped tip, or curette-cannula where the suction holes have sharp edges. Rounded or bulbous shaped cannulas, such as bullet or basket-shaped tips, provide three dimensional forces on tissue at the tip which is concentric and conical. The disadvantage of these forces in penetrating highly fibrous fat tissue is that there is likelihood of increasing trauma to these areas vectoring particularly in highly fibrous fat tissue. This force vectoring has the consequence of increasing trauma to these areas. U.S. Pat. Nos. 4,886,491 and 5,514,086 to Parisi et al, both of which are incorporated by reference, describe cannulas having bullet or rounded tips.
A spatula cannula provides a two-dimensional force which allows for greater ease of movement with less exertion on the surgeon's part. The spatula concept has been incorporated into the design of the CAPISTRANO.TM. line of cannulas. The CAPISTRANO.TM. cannulas, marketed by Jeffrey Allan Klein, M.D., Inc., San Juan Capistrano, Calif., are more rounded and the bevel is oriented more along the center-line and in longer cannulas. Any increase in roundness or bluntness causes increased resistance to passage and thus affords less predictability and bending of an extending probe within patients.
It is also known to use ultrasonically vibrating and aspirating probes in the field of liposuction surgery, as described in U.S. Pat. No. 4,886,491 to the present inventors. The procedure is to introduce the vibrating probe into the area of material desired to be removed which has been preirrigated, and use the ultrasonic vibrations to physically breakup/loosen the fatty tissue. The fatty tissue can be emulsified by ultrasound and aspirated through the probe, using irrigation as an adjunct. It is known that a particularly effective probe for ultrasonic liposuction is a hollow cylindrical probe with a bullet shaped tip on the distal end. The tip can be welded or otherwise affixed to the probe. Both probe and tip can be manufactured from a variety of acoustically conductive metals such as cold-rolled steel, titanium, and aluminum. In presently known devices, the probe and tip are manufactured from the same materials, or from very similar materials, to ensure effective propagation of the ultrasonic waves all the way to the tip of the probe. Propagation of the waves to the distal tip of the probe is desirable, because this causes the tip of the probe to be able to loosen and emulsify fat, facilitating insertion of the probe into the fatty tissue.
In previously known liposuction techniques, before the use of ultrasound, considerable physical exertion was necessary to force the tip of the probe into the fatty tissue. This was time consuming and required more openings, and it required considerable strength on the part of the physician. The currently known ultrasonic liposuction probes are much more easily moved through the fatty tissue, because the top of the probe can loosen the tissue in advance of the probe. This essentially breaks a hole through the fatty tissue, rather than punching a hole by force.
There is a disadvantage sometimes associated with an ultrasonic probe having an acoustically conductive tip, however. For instance, when the probe has been inserted into the fatty tissue near the skin or the peritoneum, resistance can be met. When resistance is met, the wattage or temperature at the tip increases, and it can increase to the point of damaging the skin or the peritoneum or nerves. During such manipulations, the heat generated at the tip of the probe may be in excess of the ability of the tissues to safely dissipate the heat. In other words, if care is not exercised, the tip may be hot enough to burn tissues, damage muscles, blood vessels or nerves, and even penetrate membranes such as the skin or the peritoneum.
Another problem regarding the liposuction procedure involves the reduction or elimination of friction caused by the motion of the cannula by the surgeon. Applying lubricating jellies and the use of plastic stents are not satisfactory since the jellies must be constantly re-supplied and the plastic stents are difficult to maintain in position.
There remains a need in the art for new devices and methods for removing fatty tissue without damaging skin, nerves, or organs or forming ridges and other disadvantages resulting from conventional liposuction surgery. A need exists for devices and methods which would greatly assist those practicing liposuction to more efficiently remove unwanted fatty tissue, especially with reduced cannula entrance wounds.